Hematology · Transfusion Medicine
The facts most likely to be tested
Febrile non-hemolytic transfusion reaction (FNHTR) is the most common type of transfusion reaction.
The pathophysiology involves cytokine accumulation in the blood product during storage, specifically interleukin-1, interleukin-6, and tumor necrosis factor-alpha.
Patients present with a temperature increase of ≥1°C (1.8°F) occurring during or within 4 hours of transfusion.
FNHTR is a diagnosis of exclusion that requires ruling out life-threatening acute hemolytic transfusion reaction and sepsis.
The clinical presentation is characterized by fever, chills, and rigors without evidence of hemolysis or volume overload.
Management involves stopping the transfusion immediately and administering antipyretics such as acetaminophen.
Prevention of recurrent FNHTR is achieved through the use of leukoreduced blood products to minimize cytokine buildup.
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A 54-year-old male with a history of gastrointestinal bleeding is receiving a unit of packed red blood cells. Thirty minutes into the transfusion, he develops rigors and a fever of 38.9°C (102°F). His blood pressure is 120/80 mmHg, heart rate is 95/min, and oxygen saturation is 98% on room air. Physical examination reveals no rash, wheezing, or flank pain. Laboratory studies show a normal haptoglobin level and a negative direct antiglobulin test.
What is the most likely diagnosis?
Febrile non-hemolytic transfusion reaction
The patient's presentation of fever and rigors without signs of hemolysis (normal haptoglobin) or allergic reaction (no rash) is classic for FNHTR, which is a diagnosis of exclusion.
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Etiology / Epidemiology
Most common transfusion reaction caused by cytokine accumulation in stored blood products.
Clinical Manifestations
Classic febrile response: temperature rise ≥1°C without evidence of hemolysis.
Diagnosis
A diagnosis of exclusion; requires ruling out acute hemolytic transfusion reaction.
Treatment
Stop transfusion, administer acetaminophen, and monitor for anaphylaxis.
Prognosis
Benign, self-limiting condition with 100% recovery rate.
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Epidemiology & Etiology
This is the most frequent adverse reaction to blood transfusion, occurring in up to 1-3% of recipients. It is primarily caused by the accumulation of pro-inflammatory cytokines (e.g., IL-1, IL-6, TNF-alpha) released by leukocytes during storage. Patients with a history of multiple prior transfusions are at significantly higher risk.
Pertinent Anatomy
The reaction involves the systemic circulation where donor-derived cytokines interact with the recipient's immune system. No specific organ damage occurs, but the systemic inflammatory response mimics sepsis.
Pathophysiology
During storage, donor white blood cells release cytokines into the plasma. Upon transfusion, these pre-formed mediators trigger a systemic inflammatory response in the recipient. This is distinct from hemolytic reactions, as there is no antigen-antibody mediated destruction of red blood cells.
Clinical Manifestations
The hallmark is a temperature increase of ≥1°C occurring during or within 4 hours of transfusion. Patients may experience rigors, chills, and malaise. Red flags include hypotension, flank pain, or hemoglobinuria, which suggest a life-threatening acute hemolytic transfusion reaction instead.
Diagnosis
Diagnosis is strictly a diagnosis of exclusion. Clinicians must perform a direct antiglobulin test (Coombs test) to rule out hemolysis. If the Coombs test is negative and no other source of fever is identified, the diagnosis is confirmed.
Treatment
Immediately stop the transfusion to rule out more severe reactions. Administer acetaminophen for fever and symptomatic relief. Do not use aspirin if platelet dysfunction is a concern. If the patient is stable, the transfusion may sometimes be resumed, but leukoreduced blood products should be used for future transfusions.
Prognosis
The condition is benign and carries an excellent prognosis. No long-term sequelae are associated with this reaction. Future reactions can be mitigated by using leukoreduced or washed blood products.
Differential Diagnosis
Acute Hemolytic Reaction: positive Coombs test and hemoglobinuria
Transfusion-Related Acute Lung Injury (TRALI): bilateral pulmonary infiltrates and hypoxia
Transfusion-Associated Circulatory Overload (TACO): hypertension and elevated BNP
Bacterial Contamination: rapid onset of shock and rigors
Anaphylactic Reaction: wheezing, angioedema, and hypotension